Prodibio Stronti+ Pro Supplement for Aquariums provides the strontium required to promote hard coral and clam growth as well as the production of beneficial coralline algae that colonize rock decor. In closed marine water reef tank environments, strontium is essential for coral development. It promotes the growth of hard corals and aids in the development of red and coralline algae, which produce the live rock decor. Stronti+ contains all of the strontium required for healthy coral, clam, and coralline algae growth.